[en] To develop a technique for mechanical tests of fuel and absorbing element claddings, tensile tests have been carried out of irradiated and nonirradiated ring samples out of the 0Kh16N15M3B and 00Kh16N15M3B steels, 00Kh20N40B, Zr+1 % Nb and Zr+2,5% Nb alloys. The samples are irradiated by a fluence of fast neutrons 1x10²¹ n/cm² with an energy higher than 0,85 MeV in the temperature range of 70 deg to 650 deg C. Empirical formula for the sample gauge length has been obtained as its direct measurement is impossible due to ununiform deformation over the ring sample length. It is shown that the test results depend to a great extent on the sample size, configuration and diameters of supports and the formula used for the gauge length determination. So for comparison of material deformability on the basis of ring sample tests these parameters should be taken into consideration. It is recommended that semicircular supports should be used with diameter being equal to 80-95 % of the sample internal diameres. For low-ductility material test prcautions should be taken not to use semicircular supports with shearings-off as well as with a diameter considerably less than the ring diameter